Messages in this thread | | | Subject | Re: [RFC PATCH] arm64: topology: Map PPTT node offset to logic physical package id | From | Sudeep Holla <> | Date | Thu, 28 Jun 2018 10:38:24 +0100 |
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Hi Shunyong,
On 28/06/18 10:18, Shunyong Yang wrote: > As PPTT spec doesn't define the physical package id, > find_acpi_cpu_topology_package() will return offset of the node with > Physical package field set when querying physical package id. So, it > returns 162(0xA2) in following example. > > [0A2h 0162 1] Subtable Type : 00 [Processor Hierarchy > Node] > [0A3h 0163 1] Length : 1C > [0A4h 0164 2] Reserved : 0000 > [0A6h 0166 4] Flags (decoded below) : 00000003 > Physical package : 1 > ACPI Processor ID valid : 1 > [0AAh 0170 4] Parent : 00000000 > [0AEh 0174 4] ACPI Processor ID : 00001000 > [0B2h 0178 4] Private Resource Number : 00000002 > [0B6h 0182 4] Private Resource : 0000006C > [0BAh 0186 4] Private Resource : 00000084 > > So, when "cat physical_package" in /sys/devices/system/cpu/cpu0/topology/, > it will output 162(0xA2). And if some items are added before the node > above, the output will change to other value. > > This patch maps the node offset to a logic package id. It maps the first > node offset to 0, the second to 1, and so on. > > Then, it will not output a big value, such as 162 above. And it will > not change when some nodes(Physical package not set) are added. > > And as long as the nodes with Physical package field set in PPTT keeps > the real hardware order, the logic id can map to hardware package id to > some extent. > > Hope to get feedback from you.
Thanks for the patch, but Andrew Jones has also posted a patch[1] which I had a look but was not sure what is the best approach to fix it yet. I will think about it and respond to that.
-- Regards, Sudeep
[1] https://patchwork.kernel.org/patch/10482261
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